As a parent volunteer I would be disappointed if that was all that was available for me to do in the classroom. While I'm happy to help the teacher with copying and checking papers and such(because it frees them up to teach), I volunteer to help the children improve their skills(reading with them, doing flash cards, reviewing tests). I would also think that having people in the classroom doing these types of things would be a distraction to the students. After all, what first grader could resist watching his mom hanging paper snowflakes on the windows when he's supposed to be doing his math?
Have you approached your principal with your feelings? What do other parents think? Does your state or district have restrictions on what volunteers are allowed to do in the classrooms? What about other schools in your state? Is this an issue just in your school or is it more prevalent? Do some research and gather information and facts, then be a force for change.
Schools in Florida get star ratings for a number of things, including parent volunteer involvement. There is lots of internally generated press on how important and desired parent effort is. It seems that what this really means is that kids never cut out their own paper snowflakes or construction paper frog, decorate the classroom Christmas tree or the classroom. While they sit at their tables doing sheet work, a team of parent volunteers armed with safety scissors, bottles of glue, and staplers do the work that used to be a reward when we were children. We'd probably be clapping erasers in the parking lot if they hadn't switched to dry erase boards.
The principal smiles and rushes off, teachers are wary and volunteers go about their crafty business. The children seem to like us and that is a big reward. But in the big picture, I resent the dishonesty of this arrangement.